1. Technical Field
This invention relates to a padlock and to a locking assembly including said padlock in which the padlock is of the so-called barrel lock type, in which locking is effected by a plunger which is spring biased to the locking position and may be withdrawn to an unlocking position against the action of the spring by use of a special key.
2. Description of the Prior Art
Barrel locks are favored as a means of securing gas and electricity meters because the lock can be installed and locked without needing to use the key, leaving intact a seal over the keyhole. Only authorized persons in possession of the key may thereafter unlock the barrel lock.
In prior art devices the plunger of a barrel lock may displace balls outwardly of the lock housing or, as exemplified in U.S. Pat. No. 4,474,041, the plunger may, in the locking position, engage and prevent relative axial movement of a stud which projects from the enclosure to be locked and which passes through a bore in the lock housing which is transverse to the bore in which the plunger is movable.
Many utility meter boxes are provided with a hasp-and-staple whereby the box may be padlocked. The present invention proceeds from the realization that a barrel lock may be adapted for use as a padlock, thereby dispensing with the need for a stud assembly projecting from the meter box. As illustrated in FIG. 3 of the Drawings of the said U.S. Pat. No. 4,474,041 the provision of the stud requires that a special opening be drilled in a side wall of the box, the insertion of a bolt through this opening onto which the stud is threaded and the provision of a locking flange and backing plate. In addition to the labor involved in installing it the stud assembly represents a high proportion of the cost of manufacturing the barrel lock assembly.
A principal object of the present invention is to provide a padlock of the barrel lock type which will be cheaper to manufacture and easier to install than barrel locks of the kind exemplified in U.S. Pat. No. 4,474,041.
In accordance with one aspect of the present invention there is provided a padlock comprising a housing, a bore in the housing, a plunger movable axially of the bore, spring means biasing the plunger toward one end of the bore, a cap closing the other end of the bore, key engagement means at the end of the plunger nearer the cap, a key hole in the cap aligned with said key engagement means and a slot in said housing transverse to and intersecting said bore, the slot being adapted to receive the staple of a hasp-and-staple fastening whereby the plunger may pass through said staple to lock an enclosure fitted with said hasp-and-staple fastening.
In accordance with another aspect of the present invention there is provided the combination of a padlock as defined in the immediately preceding paragraph and an enclosure having a hinged lid and provided with a hasp-and-staple fastening, wherein the hasp is a hasp projecting from a side wall of the enclosure and the staple is pivotable at one end relative to the lid whereby the other end of the staple may be swung through or withdrawn from said hasp, said other end of the staple having an aperture which, when said other end of the staple is inserted in said slot of said padlock, may be coaxially aligned with said bore of said padlock whereby said plunger may pass through said aperture of the staple to lock the lid of the enclosure.
The staple may be fabricated from sheet metal to be generally J-shaped and the slot in the padlock may be parallel-sided to receive the apertured end of the staple as a sliding fit.
The padlock cap is preferably in the form of a body from one end of which projects a reduced diameter spigot. An end of the housing comprises a bore of enlarged diameter to receive said spigot, the housing body having a blind bore which, in the assembled condition of the cap and housing, is axially aligned with the bore in the housing. The key hole is formed at the blind end of the bore in the cap and a compressed spring is trapped in the assembled cap and housing between the plunger and the blind bore in the cap body.
The body of the cap may be surrounded by a metal casing which extends beyond the end of the body remote from the spigot to form a crown for the body, said crown having slits through which a seal may be passed to cover the key hole.
The housing is preferably formed with a further bore transverse to the plunger bore and on the side of the slot nearer the cap through which further bore a plunger-retention member may be passed to hold the plunger in the unlocked position against the action of the spring means.
Said further bore is preferably a blind bore which is intersected by the plunger bore intermediate the ends of the further bore.
Said bore in the housing in which the plunger is movable is preferably a blind bore which is intersected by said slot intermediate the ends of the blind bore.